已知m+n=2,mn=-3,求2【mn+(-3m)】-3(2n-mn)的值
问题描述:
已知m+n=2,mn=-3,求2【mn+(-3m)】-3(2n-mn)的值
答
已知m+n=2,mn=-3,
2【mn+(-3m)】-3(2n-mn)
=2mn-6m-6n+3mn
=5mn-6(m+n)
=5*(-3)-6*2
=-15-12
=-27